'05, Air Horns and rough idle/engine after a blast

[testraub]

I have added a Compressor, 2. 5 Gallon air tank, 16. 5" Grover horns and a solinid switch. Everything works GREAT (Move over you rice driving idiot!) but after hitting the horn, the truck starts running rough and "surging" I thought it was a grounding problem but went direct to the battery for both power and ground and the problem remains. Any ideas?

 

[Cryotek]

Could it be the air compressor loading up to make up for the use of air from the tank??

 

[testraub]

Naw Compressor only hits from 120-135 PSI it's a system error I can have full pressure in the tank and still it does this I can "glide" with engine off and start the truck with no problems. But hit the horn at speed..... Surge rough... . etc... . Drivin' me bats.

 

[robert4570]

Must have been one hell of a blast them horns let out to have knocked the truck out whack.

 

[p-Bar]

could the solenoid be drawing too much current. It would have to be alot.

 

[Yo Hoot]

Must be interference coming from however you wired it. Try re-routing your wiring. Check if it's close to other harnesses that might be sensitive to emi (electromagnetic interference).



But do a test first. Disconnect the air line from the horn so it doesn't blast just to make sure it's not the actual horn itself causing it.

 

[nickleinonen]

Check if it's close to other harnesses that might be sensitive to emi (electromagnetic interference).

you should see the computer screen [crt tube] at my shop on the service track when a GE locomotive rolls by or starts up next to the screen... talk about electromagnetic interferance [the ge's use the alternator as the starter]. to see what the monitor looks like, grab one of them 10lbs super magnets and swipe it across the screen of your pc. . that degauss button on the monitor gets lots of use :-laf...





we use heavy welding cable as booster cables in my shop [±3/4" copper cable] and when boosting a unit, the cables will jump on the ground when you start cranking... lots of amps going through there. .

 

[rbattelle]

Off topic, but I'm obsessed with big machines...

you should see the computer screen [crt tube] at my shop on the service track when a GE locomotive rolls by or starts up next to the screen... talk about electromagnetic interferance [the ge's use the alternator as the starter].

we use heavy welding cable as booster cables in my shop [±3/4" copper cable] and when boosting a unit, the cables will jump on the ground when you start cranking... lots of amps going through there. .

Nick,



How is the alternator run on one of those engines? Is it geared? Is it an "ordinary" alternator, or is it the generator that provides power to the wheel motors?



How much current does the starter/alternator draw on startup?



-Ryan

 

[nickleinonen]

Nick,



How is the alternator run on one of those engines? Is it geared? Is it an "ordinary" alternator, or is it the generator that provides power to the wheel motors?



How much current does the starter/alternator draw on startup?



-Ryan

the alternators [or generators on older units] are rigidly attached to the engine flywheel/flexplate and are aligned with it [total runout like 0. 050"] it provides power for the traction motors. on the gm's there is an aux. gen/alternator that provides system power [±75vdc] for lights and controls. the gm's also have a companion alternator on most models that is a 3 phase 210vac for running the cooling fans and traction motor blower...



i am not 100% sure on how the ge systems work. . i haven't worked on them too much as we have less of them [only like 250 ge's] compared to the amount of gm's we have [probably close to 1000] and the ge's are more reliable, but when they fail, they fail big time...



i am also not sure what the current draw when cranking the engine is... the older gm's with dc generators some have generator start, but all the rest of the gm's have a pair of delco mt52 starters that are wired in series 36vdc for cranking. . all the ge's have alternator starting. i think i remember seeing a spec of like 500 amps cranking the gm starter equipped engines... 500amps at 64vdc is a lot of juice. . it might be more than that though...





in this pic, you can see the alternator under the turbocharger on the gm... the section with the loovers is the main alternator, while the section that is to the right closest to the engine is the companion alternator. .

 

[rbattelle]

Holy cow that album is awesome. :--)

 

[testraub]

Just for spit and giggles can we get back to my problem? :-laf Anyone think a 40A relay on the horn soliniod may help? I tell yeah, Dodge needs a bigger altenator for these trucks, but danged if I can find one. I also think maybe I might have at least one bad battery... . I plan on a load test on them this weekend.

 

[formula]

I've seen situations where a solenoid causes electrical interference. What happens is when the solenoid is de-energized, the magnetic field in the coil collapses rapidly and induces a reverse voltage spike. The bigger the coil, the more powerful is the spike. This can wreak havoc with electronics. It may be the source of your problem. The solution is to put a good sized diode across the coil terminals. The effect is that the diode will short out the reverse voltage spike such that it never feeds back into the electrical system of the vehicle.



Sean

 

[formula]

humm... ... ... how have you got the solenoid wired? What is the switch you're using?

 

[Yo Hoot]

This should take care of the electrical problem



#ad

 

[rbattelle]

The solution is to put a good sized diode across the coil terminals.

I'd bet it would have to be one very large diode. Get one twice as large as necessary just to be safe.



You might also have some success encasing the solenoid in a metal enclosure. That should provide a significant amount of shielding. You might also run a ground wire to the outside of the enclosure.



-Ryan

 

[THanley]

Check System Voltage

I have heard where an aux function like the solenoid will draw down system voltage to a point where the ECM does not get the voltage it requires.



Just a thought.